rubber bogie

moved my carrier from the protective car port to the barn today , like only 10 feet away, noticed something i never seen before, on the middle bogi's 3rd from the front , i noticed the rubber alittle less on both left and right sides, like a 1/2 inch or so, the prevous owner had all the bogis re-rubberd 2 years ago, and only saw very little running. the 2 bogis dosent look worn, but looked like they were made like this , is thier a reason why? also moved the carrier forward a bit, everytime the carried front raised a bit when the gas pedal was depressed , does this happen alot? or should it be smooth, thanks lads

BIG MIKE